Translating and tilting davit



1954 w. E. ELLING TRANSLATING AND TILTING DAVIT 5 Sheets-Sheet 1 Filed May 20, 1948 IN V EN TOR: Q

38F w 4 ia- 3 H. v QN UJ igh MTH mv 0 x 42 R M qa kva H WWW Kim/K1111 i l Ill ll Qwwsm 4 H H b Tl N Feb. 2, 1954 w. E. ELLING TRANSLATING AND TILTING DAVIT 5 Sheets-Sheet 2 Filed May 20, 1948 INVE1 VTOR: 2W

co e. BY 5? Feb. 2, 1954 w. E. ELLING. 2,667,649"

TRANSLATING AND TILTING DAVIT Filed May 20, 1948 5 Sheets-Sheet 3 INVENTOR. (1.3.5.

BY NWO, Kwwiog 8L Qwkhll Feb. 2, 1954 w. E. ELLING TRANSLATING AND TILTING DAVIT 5 Sheets-Sheet 4 Filed May 20, 1948 ATTORNEYS.

Feb. 2, 1954 w. E. ELLING 2,667,649

TRANSLATING AND TILTING DAVIT Filed May 20, 1948 5 Sheets-Sheet 5 VIIIIIIIIIIIIII IN V EN TOR.

CD Z By a 81 GM) Patented Feb. 2, 1954 TRAN SLATIN G AND TILTIN G DAVIT William E. Elling, Metuchen,

N. J., assignor to Continental Copper & Steel Industries, Inc., New York, N. Y., a corporation of Delaware Application May 20, 1948, Serial No. 28,191 15 Claims. (01. 938) This invention is a novel translating and tilting davit, useful for the expeditiou launching and stowing of lifeboats or other small boats from and to the decks of ships or analogous situations. In using the term davit reference is of course intended to a davit pair, there being herein as usual a single davit for each end of the small boat, these being substantially the same or symmetrically alike. The two davits also are operable in unison in a manner for their carriage or cradle members to be translated or advanced bodily, thus carrying the boat to shift it first from its inboard or stowed location substantially to the edge of the ships boat deck, and to be tilted or swung, advancingly or outboardwardly, thereby to carry the boat to its launching location well clear of the deck, with equal outreach at both ends, Whereat it may be lowered, and may be later again hoisted. These compound shifting movements of the cradles may next be eifected in reverse, with backswing for restoring the initial or untilted posture of the cradles and then for retracting bodily the cradles and boat to the full inboard or normal stowage location. With such davits, when advanced fully, the boa-t is lowered and raised by cables, wire ropes or the like, the suspension being from the heads or peaks of the cradles by means of floating blocks thereon having load hooks to receive the hoist devices or eyes on the boat.

A prior instance of a translating and tilting davit having a cradle with compound advancing and retracting movements and a, floating block and hook for boat lowering and hoisting purposes is that disclosed in the patent of this applicant granted May 25, 1943, Patent No. 2,319,854, wherein however the boat in its stowed location is necessarily well elevated above the boat deck and the davit relies upon the force of gravity for the advancing motion to carry the boat at a downward-frontward slant to bring it outboard to and beyond the edge of the boat deck whereat it may be lowered and launched. The davit structure of said prior patent is subject to certain drawbacks including the requirement of the elevated location of the boat when in stowage, and the consequent substantially steep upslanting retracting motion as the boat is restored from its launching outward location to its stowed normal inboard location.

A particular object of the present invention is to overcome the recited drawbacks of the davit of said prior patent, and especially to eliminate reliance upon the action of gravity in the advancing shift of the lifeboat from its normal inboard to its translated outboard location, and its consequent high stowed location, which may obstruct vision, even from the top or sun deck above; the present invention affording a more clear View by keeping the boat in stowage low and close to the boat deck, for example, with substantially no upward protrusion more than about ten feet above such deck, even when the lifeboat is six to seven feet high.

Further objects are to insure reliable efficiency of operation, coupled with expedition particularly in the launching of a lifeboat, and to accomplish these advantages by a davit structure which is strong, rugged, and of long endurance. A particular' object is to afford a davit which is of high convenience and ease in its operation and control, not merely in its advancing actions for the launching of a boat but in the retracting actions for stowing the boat; and to provide operations which may be substantially automatic in character by the use of a winch or equivalent source of power for restoring the davit to initial position, thus minimizing manual effort, though providing manual control under observation as is essential.

To the attainment of such objects and advantages the present invention consists in the novel davit, and the novel features of combination, subcombination, operation, construction and detail herein described or illustrated.

For facility of description, without constituting essential limitations, the following terms and definitions may be understood. Th ship, along each side of its boat deck, may have one, two or more davits, the cradle pairs or boat-carrying members of each of which are mounted for What may be termed advancing or outboardward shift from the stovving location toward the launching location and, in reverse, retracting shift toward the inboard stowing location. The term front in the sense herein used means toward the outboard location, as frontwardly from the inboard stowing location to the boat deck edge and beyond the reverse, rearward, back or inboardward direction being toward the axis of the ship. Rightward means toward the righthand of a person looking frontwardly or outboardward, leftward being the reverse thereof. Horizontal may be considered as being in or parallel to the plane of the ship deck, or whatever davit base may b positioned thereon. As to each single davit the longitudinal direction is that along which each cradle shifts or. slides translatingly so that, the operative ,cradle parts being generally symmetrical, the outboard-inboard or front-back centerline con- 3 stitutes the longitudinal axis of the davit; and parts nearer to each davit axis may be considered as inner or proxima parts, while those further from the axis are outer or distal parts.

In the drawings,

Fig. l is a general plan view of an entire davit mechanism or launching system embodying the invention, with a pair of davits, in th righthand one of which however the shiftable cradle is omitted. except as to its lowermost extremities, the better to show certain other parts.

Fig. 2 on a larger scale is a left elevation of certain parts of either davit, partly in vertical section on the line 2-2 of Fig. 1, a certain track being omitted.

Fig. 3 is a top plan view on a further enlarged scale of certain details of Fig. below the line 3 of Fig. 2.

On Sheet 2 Fig. 4 is a general left elevation on an intermediate scale showing the cradle in its extreme retracted location and upright posture, with'the boat inboard in stowed location; while in dotted lines the parts are shown in their other extreme location, the boat being outboard ready for launching and the cradle being at its full advanced location at the front and in its tilted posture.

Fig. 5 on a larger scale shows the lower part of the cradle and cooperating elements, as seen in back view and shown partly in section taken on the line 5-5 of Fig. 1.

Fig. 6 is a front elevation looking in the direction of the arrows 6-5 of Fig. l and showing certain details of the davit operating means or energizing spring devices.

On Sheet 3 Figs. 7, 8, 9 and 10 are similar perspective views of either of the davits, these showing four of the successive positions of the'parts in passing from the fully retracted or stcwing location of Fig. 7, through the fully advanced cradle location of Fig. 8, and the partially tilted cradle posture of Fig. 9 to the fully tilted or launching position of Fig. 10.

On Sheets 4 and 5 Fig. 11 is a the cradle head or peak and the means for suspending the boat therefrom. Fig. 11a. is an explanatory detail thereof. Fig. 12 is a front elevation thereof, looking toward the left side of Fig. 11. Figs. 13 and 14 are like Fig. 11 but showing other positions of the parts. Fig. 15 is a left elevation and part section of the suspension mechanism, Fig. 16 being a vertical section on'the line lit-It of Fig. 15. Fig. 17 is a perspective view of'an important unitary member or block constituting part of the cradle head.

The invention may be preliminarily outlined as consisting in a combination of mechanical elements cooperating in the manner to be hereinafter described in detail and affording the advantages and results hereinabove indicated. In one aspect the important elements and their mode of combination are as follows. Upon the ships deck iii are movably mounted, in spacedapart relation somewhat less than the length of the lifeboat IQ, two single davits 18 that are substantially similar or symmetrical in structure and operation, each davit comprising in combination with its cradle or boat carriage 20, shiftable frontwardly toward the deck edge and thereupon .swingable or tiltable outboardwardly to bring the boat to launching position, a system of tracks or fixed and movable bars for guiding and controlling bodily shiftingand the tilting or swinging at east h e force which shifts the cradle bodily 2 looking downward I left elevation of V ernents of the cradle; the actuating forces, or

4 frontward, being supplied by energizing means other than gravity, preferably spring devices that are rechargeable after each launching operation; and together with such elements a system of transmitting cables, chains or ropes, having means for clamping the terminals thereof and for guiding their intermediate portions; all mounted and combined as will be described or equivalently to afford the desired mode of action during launching and stowing operations.

Referring to the drawings, showing the complete apparatus, and separately showing the structure of each davit, the lifeboat or other small boat it is partially indicated in broken lines in plan view and in elevation, and in its inboard stowed location and its outboard launching location, the bow and stern ends H, H of the boat being indicated. In order to connect the boat ends to the davit system for lowering and hoisting purposes and to disengage the same, the boat is shown provided with a hoisting device or eye 13 near each end of the boat to engage the coupling hook 3 1 of 'each davit. These hoist fittings may be on the same principles as the showing of the corresponding parts in said prior Patent 2,319,854.

Each single davit is mounted upon a base 15, which may be the boat-deck of the ship, upon which the fixed members of the davit including the fixed cradle tracks may be rigidly secured, as by bolts or by welding. In the plan view is indicated the outboard edge 15 of the ships deck, each of the davits being mounted with itsfront end, i. e., the front ends of the fixed parts or tracks. in close proximity to such deck edge, so that when the two cradles and the carried lifeboat are advanced frontwardly the boat will be carried well beyond the deck edge It to a launching position which may be safely available whether the ship be steady on an even keel or be under a roliing action or listed to a moderate extent.

Each of the individual davits I8 comprises as one of the fixed parts a hollow backpost [9 near the inboard end of the davit. These elements being substantially or symmetrically identical, it is sufficient to describe indetail only one of them, namely, the lefthand davit including its hollow post, the latter carrying and partly enclosing certain important mounting and guiding means as will be more fully described.

One of the more important elements of each singledavit is the cradle or boat carriage 2B, which is preferably a unitary member upstanding fromits mountings, and adapted bodily to shift frontwardly to the limit, in unison with the corresponding cradle of the righthand davit, and therebeyond to tilt or swing out further and downwardly carrying the boat well beyond the deck, these motions being reversible to restore the cradle to its back-tilted posture and to return it rearwardly or inboard with the boat to the stowing location of the latter.

The cradle 20 is in the general nature of a floating lever, with no fixed part or pivot, but having mounting and guiding means adapted to permit its translatory and tilting motions described; and while its design may be indefinitely varied a preferred form is illustrated as next described.

The cradle, which may be composed of a strong, light and non'corrosive metal, such as an aluminum alloy, may

comprise at its middle por-' tion its upstanding body 2 i, from the upper front ment with a symmetrical a bent or crooked formation which provides beneath the neck an ample recess to accommodate the half-width of the lifeboat throughout the operative movements of the davit. At the front end or terminus of the neck is the davit head or peak 23, which carries the floating block 25 and the load hook I34 for boat suspension purposes, as will be further described.

Each cradle below its body portion 2! is specially formed with a depending extension or front leg 25 and well to the rear thereof a back leg 3!, one of which, the front leg as shown, being forked laterally, the two sides of the fork, left and right, being the branches 23L and 26R depending to their lowest ends or feet 21L and 27B. This forked construction of the cradle front leg 25 not merely straddles and thus clears the central parts of the davit mechanism at this point, but affords, alon with the rear leg 3|, a three-point operative mounting of the floating cradle, greatly strengthening and stabilizing its action during translating and tilting movements. In a sense, the forked lower construction of the cradle front leg is but a spread or widened leg, not merely for stability but also to provide for the front leg an offset relation to the more centrally arranged back leg 3|, that is, offset as to the davit axis, so that the guiding and controlling means for the front leg and back leg respectively may be accommodated without interference.

Each cradle therefore is provided, at its low extremities, with the aforesaid pair of symmetrically spaced-apart front feet 2'lL and 27R and with a centrally arranged back foot 32; and by the guidance and control of such three feet the desired operative movements of the cradle are effected. For cradle guiding purposes the several feet are provided at their left and right sides with outstanding guiding studs or rollers arranged to engage in the grooves or slots, which may be termed ways, of certain tracks to be described. Thus each of the front feet 21L. and 21R carries an outer or distal stud 28, these two studs 28L and 28R projecting outwardly into engagement with an outer pair of trackways 4|, which are secured fixedly to the base or deck. Each of said front feet also carries a proximal or inwardly projecting stud 29, these two studs, I

29L and 29R, extending inwardly into engagepair of front-hinged swinging tracks 42. The arrangement is preferably symmetrical throughout, the tracks being in symmetrical pair-s, left and right, the fixed tracks being at the outside, the front-hinged tracks being intermediate, and inwardly of these being a central symmetrical pair of back-hinged tracks 43, the cradle back leg 3! having, on its foot 32, opposite guide rollers or studs 33, marked 33L and 33B for left and right, engaging with said back-hinged tracks or the grooved or slotted ways thereof. The roller studs 28 and 29 at each side turn on a short cross axle 30 mounted at the foot 27 of the fork branch 23. Between the midpart of each branch and a higher point on the leg 25 extends a brace 24, and this is continued vertically downward to the foot end 2? of the leg branch.

At the foot of the back leg 3| depending from the cradle body, at the axis of the davit, is the opposite pair of rollers or studs 33, left and right of the center, marked 33L and these turning loosely on a short cross axle 34 carried by the foot and engaging in the ways of a pair of back-hinged tracks 43 of channel form connected by an underneath cross-plate ed to swing in unison. Thus the cradle takes its stance by its three feet 21L, 21R and 32, each carrying roller studs in pairs, 28, 29 and 33 cooperating respectively with each of the three pairs of tracks 4|, &2 and 43.

The use of transmitting cables has been referred to, to be further explained as to their paths and functions, a primary cable a: being operated by a spring energizing device or motor to be described, which can exert forcible pull to slide the cradle frontward toward launching position; a secondary cable y being operated by a winch (hand or power) to pay out the cable for launching and to take it up for stowing purposes; the cables passing around sheaves at various points-including sheaves on the cradle and also at the hollow backpost l9 and other fixed locations. Cable ends must be anchored or clamped, and there is shown for anchoring the primary cable ends to the cradle front leg or its forks 26 at each side of the cradle a positioning projection or pin 35 around which the cable passes on its way to a permanent clamp 36 on the cradle fork brace 24. The secondary cable for each davit is attached to the winch and at its second end is anchored by a clamp 31 at any convenient fixed location preferably at the interior of the backpost.

Referring next to the three pairs of tracks, providing ways for the movement of the rollers 28, 29 and 33, these, commencing with the outer or distal tracks consists of a stationary track pair 4i, arranged symmetrically at the extreme left and right of the davit, each track 4| having a foot flange by which it is secured or welded to the base or deck [5, and each having a top flange ii extending inwardly and underneath which runs the roller 28. Next in order is the fronthinged track pair 42 mounted so that the rear end of the track pair may swing upwardly and downwardly about the front axis, and each of these tracks being formed as a channel to provide a way for the movement therein of the rollers 29. Lastly is the back-hinged track pair 43 fulcrumed to swing upwardly and downwardly at the front end of the pair, these also being of channel form to provide ways for the travel therein of the rollers 33.

The fulcrum or hinge pins of the front-hinged tracks is located at 45, in line with the front end of the fixed tracks 4|; and as shown in Fig. 5 the two tracks 42 are interconnected at an intermediate point in their length by an underneath cross plate 43, upon which the tracks are attached or welded, this cross plate having also an upstanding double bracket 41 and a spur 49 for purposes to be referred to. I

The back-hinged track pair 43 is shown as fulcrumed by a hinge pin 59, enclosed within the housing of the back-post !9. This track pair therefore is extended much further back than either of the other track pairs, but at the front end is relatively shortened, as seen in Figs. 1, 7 etc.

The three track pairs are cooperatively associated to bring out the desired movements of translation and tilting of the cradle. Thus, when the cradle is in its extreme back position, as in Figs. 4 and '7, its back leg 3! cannot rise to swing the cradle because its rollers 33 are engaged in the tracks 43, while the rollers 29 are engaged in the tracks 42 and the outermost rollers 28 in the fixed tracks 4 I, the last mentioned preventing any tilting of the cradle until the cradle front rollers 28 and 23 have shifted frontwardly through the intermediate position of Fig. 8 to the-extreme front position of Fig. '9. When the cradle reaches that position its rollers 28 and 29 come into alignment with the fulcrum axis 45 of the tracks 42, thus releasing said traclrs ,o be swung upwardly in the manner indicated in Figs. 9 and 10. In other words, the fixed pair of tracks 4! look down the front-hinged track pair 42 until the cradle .has been shifted to the limit of its frontward shift, where it is stopped by flanges or blocks 48in the ways of tracks 42. The translatory front sliding :of cradle must therefore be completed before tilting can begin in the manner apparent in Fig. 8.; whilethe sliding retraction cannot begin until the cradle is again restored to upright posture. The-baclr-hinged tracks 43, which directly control the tilting rise of the cradle bac: leg, enter into this operation by reason of a running connection between thesetracks and the front-hinged tracks 42. This connection consists, at each side of the axis, of a mechanical interconnection between the adjacent tracks 42 and 43, shown as a secondary guide or channel '51! at the outer side of the track #3 and a projecting'slider or stud 53 at the inner side of the track 42', the stud engaging the channel. Thereby the lowered tracks 42 hold down the tracks 43 and the cradle is compelled to move with horizontal translation and no tilt until it has reached its extreme front position. When at its back and intermediate positions the stationary tracks hold down the front-hinged tracks in their normal or initial position, as stated, and these in turn, through the connection iii, 53, hold down the rear-hinged tracks. This track pair in turn holds down the central rear leg of the cradle, precluding any tilting of the cradle except in sequence after the completion of the frontward shift thereof, when the track pairs 42 and 63 can swing up, oppositely in crossing relation, controlled by the guide and sliding pivot 53, and through the Fig. 9 to the final Fig. or launching position of the cradle.

Preferred devices t!) and 54, acting on tracks 42 and 133, to be described hereinbelow, serve respectively to promote frontward or outboard tilt- 1 ing of the cradle for launching and return tilting to upright posture. l

The invention provides an energizing means and continuous force arranged for shifting frontwardly the cradle and tracted position of Figs. 1, 4 and 7 to the advanced position of Fig. 9, not relying upon'the negligible gravity force afforded by a sloping deck, while obviating'a design wherein the boat has a highly elevated stowed position. .The energizing means is resilient and a spring device or motor 5! is shown, being essentially a pulling device acting through a cable x extending to the cradle; the spring being constantly charged or highly stressed, with stored power, to urge the cradle frontward, and providing adequate motion for the complete frontward shift; the action being under .control at will by means of the winch, .acting preferably through another cable :11, the winch paying out its cable for launching actions and taking it in for hoisting and stowing .actions, which latter act to restore the full charge of the spring motor.

The spring motor 51 may be of different types so long as it provides the pulling force and the necessary length of throw or stroke. It is shown as embodying a helical spring 58 of straight form, with normally open convolutions so that the spring is shortened by charging or placing it under stress. As a specific example the spring may the boat from the rebeformed from a .inch steel rod, wound to a 4 inch helix; such a springv affording an; operative expansion of 15inches, leaving ample stored power to complete the shift of the cradle. When full-charged the convolutions may be under .almost solid contact. This expansion throw being insufficient, there is provided 'a suitable means of multiplication of movement, so that said spring expansion may afford in the cables and cradle an ample throw for the full distance of cradle shift between its front and back positions.

The energizing spring 58 is preferably housed for its protection against deterioration, such housing being shown as a pair of aligned telescoping tubes or barrels, including an outer barrel 59 with a closed end iiiiiforming a seat for one end of the spring and an inner barrel 6| having a closed seat 62. These parts are shown in Figs. 1 and 6.

The spring motor 51 is mounted on the davit base or ship deck, preferably in a midway position between the davits i8, 18 of the pair, so that the device may supply the energizing force for shifting frontwardly the cradles of both such davits. The outer barrel 59 'is provided with mounting flanges-6 1, at both longitudinal sides, these being secured at the top sides of a pair of short columns 65 which in turn are welded or otherwise secured to the base 15.

The encased spring 58'and its telescoping housing represent the spring motor and it will now be described how said motor is embodied as a part of the operating mechanism. At the back end of the inner tube 61, its closed end 52 carries a pair of cars 61 for the attachment of a member 68 in the nature of a head or crossbar, which in Fig. 1 is shown in full lines representing the stressed condition of the spring,and in dotted lines representing its partly relaxed condition after the spring has performed its work of pulling frontwardly the .cradle. It will be understood that in one extreme position of the spring motor parts the spring will be stressed to its maximum as it yields and becomes compressed during retraction of the cradle; while at the other extreme position the spring becomes relaxed only partly, to a predetermined minimum stress, ,and is never fully relaxed, wherefore the spring functions to deliver constantly an effective pulling force upon the cables through which the cradle is advanced frontwardly.

Reference may now be made to the means for multiplying the motion of the inner tube. As a motion-multiplying means, which might be of various types, the principle of the block-and-tackle is illustrated. This instrument comprises a series of sheaves it mounted on a bracket '3 E, duplicated at each side of the spring motor, the brackets being supported on the telescope flange 6 1. Similarly, at the ends of the crossbar or head 58 is a similar series of sheaves '53. By this arrangement the primary cable, designated generally as ."c, is passed alternately around the front sheave series or block, in fixed location, and the movable rear sheave series or block. Assuming two sheaves in each block, there would be four strands of cable, thus multiplying by four in the cable pulling movement the length of the spring-produced outward movement of the head or bar '68; and taking the latter as 15 inches, the multiplied movement would be 5 feet which, if insufficient, could be readily increased by adding further pulleys to the blocks in and 13, for example, with eight strands traversing the inner and outer blocks afforded at theclosed end there would be 10 feet of movement in the cable portions extending to each davit and cable.

We may now trace the spring-produced cable pulling actions by reference to Figs. 1, 7 and others. The entire mechanism to be described is duplicated for the two davits, and therefore need be described only for one thereof. The'first end a of the cable is anchored fixedly by a clamping or holding device i5 located between two sheaves 10. From there an extended length r l of cable is passed alternately around sheaves of the block 13 and of the block 10. From there a length m of cable passes to a coupling m whereat the single cable extending to that point may be connected to a pair of cables 112 thus providing duplicate connections from that point on, to afford a symmetrical frontward pull upon the opposite front legs of the cradle. Both of the cables x pass thence around a double-grooved idler sheave x mounted on a bracket 76 on the upstanding post l9. From the sheave x one cable passes directly frontward, the other extending first across to the opposite side of the davit, and around a sheave mounted on a bracket 77. Both cables thence extend frontward at to Where they pass around pulleys :0 located fix edlyat low points, as on the outer sides of the fixed brackets ll. From these sheaves r the symmetrical cables next pass to and around the anchor pins 35 on the cradle front leg, and finally to the anchoring clamps 36, already mentioned, at a higher point on the cradle leg. Thus when the boat is in stowed position and the spring motor is allowed to operate, the cable at extending from the motor, and eventually clamped at the two sides of the cradle, pull symmetrically and forcibly frontwardly thus to shift the cradle toward launching position, all under the control of and as permitted by the action of the winch as will be described. In any case where a greater spring pulling force is required the telescoping casing for the motor spring could of course be double or multiple barrelled to accommodate one or more additional springs.

The winch tie is a convenient means, acting through the cable y, for operating and controlling the general launching steps and the reverse or restoring and stowing steps, aided by the spring motor 51' and by the gravity of the suspended lifeboat iil. Each of these general operations comprises three phases or stages. In the launching operation the winch pays out cable, first, to allow the motor to pull the cradle from its back to its front position (compare Figs. 7 and 8), the cradle remaining upright and this motion being stopped by the barrier 43 in the tracks 32; and second, to allow the frontward tilting of the cradle to occur, aided by the secondary spring motor 5 to be described and the weight of the boat, the final tilted position (Fig. being stopped by a flange or barrier 52 in the front end of each secondary guide channel 5| carried by the tracks 32; and third, to give out more cable to permit the lowering of the boat from the outswung cradle head. The reverse general operation consists in the opposite steps, the boat being first hoisted from the seat to the cradle head, the cradle being then upswung to its normal upright posture, the retraction to stowed position finally occurring while the taking up of the cable by the winch eifects the recharging of the spring motor 57.

The winch Se is shown conventionally as representing any type of winch, having a body or frame portion 8!, which may be located at any 10 convenient point on-the deck, preferably adjacent to one of the two davits as shown in Fig. 1. There are two cable drums 82, one for operating each of the two davits, and the two working in unison as is necessary to lower the boat in a level position. The drums are mounted on a common'drum shaft 83 which may be rotated by means of a worm-and-wheel mechanism 84, the worm being carried on the winch drive shaft 85. A motor 88 is indicated for the operation of the winch and preferably there is also a hand drive or crank 8? for emergency operation. Means to hold the winch against rotationis necessary and this is shown conventionally as a braking means, comprising a brake wheel 88 upon which is indicated a brake shoe or band 89, with a manual means or lever to apply and release the brake, said lever carrying a counterweight 9i sufilcient to hold the winch and the cables normally against operation.

The action of the winch will be better understood by outlining the disposition-of the cable y, thus indicating the other elements with which the cable cooperates and laying the basis for describing the triple functions alforded by such a cable when payed out and taken up by the winch. Starting with the winch, what may be considered the first part or end y of the cable 3 is anchored or attached to the winch in the sense of being Wound upon its drum 82. Figs. 1 and 9 fairly show the arrangement and indicate that there are two drums, for operating two separate cables 1 extending to the two davits, so that only one drum and one cable 1 need be considered in this description. From the winch drum extends a length of cable, which first passes around an idler sheave 1/ mounted on a fixed bracket 93. Therefrom is a stretch y of cable extending to a davit and passing around a low sheave g located inside of the back post 19. Therefrom an upstretch y of cable passes around a high sheave y' within the hollow post. From the post the cable extends frontwardly as a stretch 1/ passing to the cradle, and around a, sheave g at the righthand side of the cradle body 2|. The cradle bodysheave 1/ may be at approximately the same level as the sheave 1,! at the top of the post, so that the cable extends between post and cradle in a manner and at an elevation to avoid conflict with other parts of the davit. After passing around the cradle body sheave 21 there is an upstretch 11 passing over a guiding sheave y at the neck of the cradle, from whence the cable extends further front.- wardly as a stretch 1 leading to the first or righthand side pulley IE8 at the head or peak of the cradle. Passing over the righthand head sheave Hi8 the cable is formed as a depending loop, with a downstretch 2/ leading to and around a suspended sheave I36 and thence upwardly by a complementary stretch completing the loop, said upstretch passing over a left side head sheave I09, as seen also in Fig. 4.

Continuing the arrangement of the winch cable y, from the head sheave I09 the cable next comprises a stretch extending along the left side of the cradle head and neck to a left side sheave 1,1 which may be arranged oppositely to the right side neck sheave 1/ Therefrom the cable extends downwardly as a stretch 1/ to a left side body sheave 1/ From the leftbody sheave 1 the cable extends as a backstretch from the cradle to the hollow back post.

It will thus be noted that the return or backwardly extending stretches of cable y largely parallel in their positions the frontward stretches,

.in the post by the cla'mper 81 already having a first from the winch tothe .cradle head andcomprisbut of course with opposite directions of 'disposal; and this plan might be continued by continuing the stretch 1 reversely along the path corresponding to the path first travelled by the cable in passing from the winch to the post and the cradle; but in that case it would be necessary for each winch drum to carry two cables, or else provide supplemental drums for the purpose. A preferable arrangement is that which is shown, the backstretch 11 of the return portion of the cable passing merely over a dummy pulley or other grooved device W, the cable second end @1 being therebeyond clamped to a fixed point described. As shown, the total cablemaybe considered as or travelling branch extending ing the several sections from y to 111 and a second or non-travelling branch. extending in successive sections from @1 to 11 thisarr-angement effecting an increase ordoubling. ofpower at the distant points; such .as...the. suspended sheave 136.. For. example,..if the: winchtakes up, say 6 -feetof cable, this causes. travel only of the first branch. ofcalole, and. theboat, ,for example, will be hoisted only half ofi.that1distance,..or 3 feet, with consequent doubling of power.

The. suspension of each boat end from one of the cradle heads 23 may be by a floating single block containing a, sheave, such as list, around which the depending cable loop p y passes; and which block therebelow carries or isformed with a conventional load hook ISA, shown in Figs. 11 to 13, or other coupling adapted to en- .gage with and disengage from the hoist eye I3 of the boat. For quick uncoupling of the hoist eye and boat any type of slip-hook may be used.

.Figs. 11 to 1'7 show an advantageous form of suspension adaptedfor use with davits having outwardly tilting cradles such as the one hereinabove described, with cradlehead sheaves I63 andIIlQ over which pass the cable portions that form the hanging loop ylf in. which the float,- ing block sheave I35 rests. In left elevation Fig. 11 showsthe cable sections y to 11 at the neck 22 andhead 23 of the cradle,with head sheaves I68 and IE9, and with block. are containing sheave I36 hanging by the cable, the hook I34 being atthe bottom of the block; the cradle being seen in its upright posture. The same parts. are, seen in the partialfrontelevation of Fig. 12 viewed from the left. of Fig. 11. Fig. 13in left view similar. to Fignll shows the neck andhead portions of thecradletiltedto its. most outboard posture; the. sheave. pulley or. block assembly being shown almost fully hoisted, to where ithas contact with .the cam portion of the lower jaw of the-spacer blockiifl l to be described. In Fig. 14, similar to Fig. 13, is shown. the sheave block or, pulley assembly retracted relatively upwardly by thev cable pull still further to its limit position, between the jaws II? and II8,.preparatory to co-acting with the cradle to bring the lifeboat to its inboard and stowed positions. Fig. on a larger scale is an elevational view, partly in. section, of the cradlehead, and the interior core or block; I65 thereof which serves both as a spacer or. fillerv for the head plates and as a jaw carrier. Fig. v1.6 is a vertical cross section taken on the line l t-I5 of. Fig. 15. Fig. 1'7 is a perspective view on a reduced scale of the filler. block or core I04 shown in Figs. 15.and 16.

7 These figures show the cradle head. 23.. to..be .built up. as a filled rectangular box-like. struczrope pulleys I91 frame metal shaped around it.

identical shape, being continuations of the side's of the cradle .body and neck and terminating at IIJI, while channel members I02 and I03 form the top and bottom respectively of the head structure.

..Bolted inside the cradle head is the core block oncasting I04 which acts as a filler and spacer for thewalls IBELIM, I93; and securing bolts I are received in aligned holes in both upper and lower channel .members I02: andnl 03.1 and pass throughholes in thespacerblocklcs.

The spacer. or core piecelfld acts also-as aboaring support for a pin. orifixedaxle :Ibfi, Figs. 15 and 16, which projects throughithe side walls Hit and. has mounted exteriorlyon its opposite .ends, left and right, the two cable-sheaves .marope pulleys I01 and I.08,:independently rotatable and running on ball-bearings Ie9,.all heldin-placeas by nuts" I II), threaded on theshouldered-axlepin I65. Two. annular spacing .washers I.It,-.-.positioned against thewalls Iilll and surrounding .the axle I56, ensure plane alignment of the pulleys I07 and I08, with the pulleys y and y and others mounted on the cradle neck and body.

The side walls IIIii are provided with angle-iron ears II5, whichmay be secured to the .wallsby rivets, welding, or other means. The outer wing H6 of. each angle iron projects over one of the and I08, and these wingsare spaced from the pulleys enough to allow ample running room for therope, but not enough space to allow the rope to jump the pulleys.

The head or peak '23 of the cradle also carries and includes upper and lower jaw members Ill and H8 respectively, preferably-unitary or integral with the body I IQ of the head core or block I04. The upper jaw H1 is of substantially the full width of the core block body H2, the. lower jaw member I I8 having a lesser width, and having a downwardly inclined stem I28. The lower jawhas a hardened thin metal sheet or wear plate I2I, encompassing and sheathing its working surfaces and secured thereon by screws I22.

The purpose of these shapedheadejaws is .to form between them a recess or mouth I23 to re: ceive a top cross member or rod I31 being part of the frame I28 of the pulley block lZB which care riesthe floating sheave I36. Actually the, cross rod may be surrounded by part of the pulley and the. latter considered as the cross member. The underjaw acts also to steer such cross member into such mouth as thecable pull completes the hoisting of the boat. The said mouth I23, so formed by the upper and lower jaws Ill and H8, terminates in a throat at a rear mouthwall I24. The circular contour of the rear wall of the mouth recess ex: tendsslightly more than a semi-circle, thus providing a notch I25 in which may securely hang pendulum fashion by. the cross piece I3'I the pulley block orfioating sheave assembly I25. of whichthe sheave IE5 is a part, as best shown in Fig. 11.. A roof portion I21. of such mouth is shaped to cooperate withthe bounding portions I24 and 25 to provide a slight constriction. By these configurations the jaw mouth and throat cooperate with the upper cross member I31 of the sheave pulley assembly or block frame I28 as will be hereinbelow further described.

The floating block I26 as a whole comprises the sheave or pulley I38, and the block frame or shell I28. in which it .ismounted. Said pulley block frame as showncomprises a one-piece bent 13 sheet metal member I29 to I33 and I40 formed substantially like a narrow inverted-U, with a body I3I constituting the opposite cheeks of the block, and with depending leg plates I29, I30. Above the body the sheet metal is extended as an upstanding column I40 having the inverted-U shape and at its top giving support to or combined with the short cross rod or pin I3'I which is the part of the block assembly that is adapted to enter the cradle head jaw mouth I23 when the boat is hoisted. The metal of the inverted-U column is cut away as a large oblong aperture as seen in Fig. 12 to admit and straddle the narrow lower jaw H8 as the cross stud I 3! enters the mouth to pass into the throat between the jaws.

For strength of the suspended block I26, side plates I32 are welded to the inverted-U portion I3I, affording a brace therefor; and a transverse brace I33 is welded to the lower ends of the body portions I 3 I, where they extend below the sheave. The leg portions I29 and I are connected and braced by being welded to the upper portion of the load hook I34, thus rendering this hook, which is to engage the hoist eye I3, a unitary part of the floating block frame I28. Mounted in said frame between the bracing members I33 above and I34 below, is the axle or stud I on which is mounted and rotates the loose pulley or sheave I36, around which runs the depending cable loop 11 which loop is taken up by the winch pulling on the cable part 9' only. Near the top of the inverted-U portion I46 of the block frame, and welded at its ends to the side plates I32 is the suspension cross pin or rod I31 which, in the position shown in Fig. 11, rests in the mouth notch or throat I25; the upstanding extension I being cut away to provide the aperture I38, of sufficient width to receive the lower jaw member II8 as the pin I31 enters the jaw mouth. The jaws I I1, I I8 are shaped to steer the pin into the mouth by the path I23, shown in Fig. 13. The under jaw has a cam surface I39 which forces or cams frontward the pin as it rises with the hoisting of the boat. On passing off the cam I39 the pin naturally shifts backward, along the top surface I4I of under jaw I I8, between the jaws, and the shape of the under side of the upper jaw cooperates in this action.

In operation, the cradle 20, we may assume, has moved from its inboard to its outboard position, and has tilted frontwardly from its Fig. 11 to its Fig. 13 position, as shown also in Fig. 4 in dot-dash lines, for the launching of the lifeboat. At this stage, a continued paying out of the winch rope y, allows the pulley block cross pin or suspension rod I31 of each davit, to slip frontwardly from the notch I25, and downwardly along the upper surface I4I of the sheath-covered lower jaw II8 to disengaging position; and the parts are then in position for the lifeboat I0 to be vertically lowered. From the winch the lowering is effected and when afloat each load hook is unhooked from the hoist eye, to be later engaged for rehoisting.

In the reverse of the cycle, the steps of raising and stowing the lifeboat are effected from the winch. The actions are best followed on Fig. 13. The winch rewinds the rope y thus raising the floating block and sheave assembly I26 vertically, until the inverted U-shaped portion I40 or pin I3! of the block frame strikes the cam surface I39 of the lower jaw member II8; further hoisting by the rope 3 causes the block or assembly to be directed and displaced first to the left,.by the cam I39, until it reaches the top end of the cam surface, and then to the fight-through the mouth I23, until it is stopped by the rear wall Continuance of the rewinding of the rope .y

will draw the inverted U-shaped cross portion I40 or I31 up into engagement with the roof I21 of the notch I25 of the mouth I23; so that the continued taking up of cable by the winch starts the outswung cradle, as illustrated by dot and dash lines on Fig. 4, towards it normal upright posture. Therebeyond, no further untilting being possible, the winch, opposed by the spring .motor 51, causes the back sliding of the cradle, crosswise of the deck, until the boat reaches its furthest and fully stowed location, where itmay be secured by the winch brake holding the position or by supplemental or safety iocking means. The winch cable block 26 is thus a suspended or floating element combining the sheave I36 and a block-frame unitary with the load hook I34; and combining also the overhead extension, reaching well above the sheave, which has a cross part that cooperates with mouth jaws or cams on the cradle head by which the block has a definite and stable cooperation with the cradle both before lowering and after hoisting the lifeboat, continuing until the davit and boat reach their normal position, meaning full-stowed, with boat raised and'cradle upright.

During launching, when the tilting has commenced, the retarding as by thewinch brake is indispensible, since the full weight of the boat is in action tending to accelerate front tilting and lowering. The winch may be power driven by a portable motor, to be taken out of exposure when not in use. A conventional centrifugal brake or winch governor 8B is desirable for safety purposes, to prevent the lowerin of the boat from exceeding a reasonable speed as feet per minute.

The weight of the boat always tends to tilt frontward the cradle, as is seen by the normal overhang e indicated on Fig. 7 between vertical lines drawn through the block I25 and the front hinging rollers 23, 33 on the front legs of the 3- legged cradle. Likewise, the force resultant of boat gravity and spring pull make for cradle stability. The spring pull of cradle is ample by choice of springs for the motor. If the spring stress is 4 tons, there will be 2 tons for each davit; while the block and tackle i9, it reduces this in the ratio 4 to 1, so that ton is delivered by way of two cables to the cradle, to slide the latter frontward 5 feet in the example described."

The following are two advantageous supplements to the arrangement of a spring-energized three-legged sliding and tilting cradle cooperating with stationary, front-hinged and backhinged tracks in pairs. When the cradle has slid fully frontward and is ready to tilt outboardward, the weight of the boat, especially if loaded, affords a relatively small tilting force at the start, due to the small overhang .2, Fig. 7, becoming greater as the tilt proceeds. The first expedient is to avoid relying on gravity; for which a device 54 is shown adapted to bias the tracks 42 and/or 43, especially at the start, for their joint upswing thereby to promote the cradle tilting,

under control of the braking action of thewinch. Such device is'preferably resilient. and is shown as a lengthwise'expanding spring motor :54. (with springenclosediin a telescopinggcasing like the motor Elalready described) fwith'itsxfront. end fulcrumed on thebase by a pivot 55'; rearwardof, hinge 45, and upslantlng .rearwardly ,to' where the motor is connectedby a pivot '56, to. the-bracket 4'1. upstanding from the .crossplate 4.6. of the track pair :22. See Fig. 2 wherein theupswing efiect is shownin dotted.lines;.and.se.e also Figs. 3,- 4, 5 and 10. The frontpivot 55 of themotoris lower than a'lin'e drawn from its back pivot 55 to the track pivot 135,. therefore the upswinging effect of the expanding motor is always in sheet, with no dead-center effect. In Fig. 2 the rear-hinged track 43 is wholly omitted to disclose the track beyond.

The. other expedient or device 49 promotes the hacker return tilting of the cradle at the time when thewinch takes up cable y for that purpose. When the tracks 42 and 43 are fully upswung, as 'seen in Fig. 10, the cradle head 23 being fully outboard, each of the tracks 43, for swinging. down again, may have an initial tangential direction of downward motion which approaches a right angle to the direction of its guide channel or way 51 in which the runner 53 of track 42 plays. That channel has to depress the stud or follower 53 carried by the track 42 in order-that both 42 and 63 may swing down in unison. ,It desirable to provide against any dead centereffect at this point which mighttend to. impede or block the start of the downswing of these tracks. This object is by any mechanical supplement acting on the tracks to start their downswing, or otherwise acting. to cause the stud 53 to slide rearward in the channel 5|, thereby avoiding the need of relying on the downthrust of the track 43 caused by the cradle swing. An effective expedient is the extension finger or spur 49, single or double, seen in Figs. 2 and 3, which projects rearwardly from the upstanding bracket 41 which in turn is a rigid portion of the cross plate that unites the two tracks 42, 42. By depressing th spur 69, or any other rigid part of the tracks 42, the downswing ofthetracks 42 and 43 is effectively started without-any tendency to impede the action. The spur. 49 is so shaped and located that its upper surface, when these tracks are fully upswung, is substantially in. underneath contact with some part of the cradle, such as the bottom end of the rear foot '32. of the cradle, as clearly appears in Fig. 2. The result of this arrangement is that, after the boat has been fully hoisted, and the winches operate to take up further thecable ii, the backtilting of the cradle starts, the back leg 3| and foot 32 swinging downwardly toward'the rear, thus acting on the spur extension 49 and depressing it along with it the track pair 42 in its entirety; thus effectively starting and continuing the downswinging of both trackpairs 42 and 43, the continuing and finaldownswing being eifected by the direct downthrust of the cradle rear foot, acting through the ways of the back-hinged tracks 43; thus overcoming th possible tendency of impedance or blocking'of the retilting of the cradle to its normal upright posture.

There has thus been described a translating and tilting davit, resiliently orspring energized, embodying the principles and attaining the stated objects of the present invention; and since many matters of combination, subcombinatiom operareadily accomplished frontmc-st position;

;, its irontmost position,

16 tion, construction and detail maybe variously modified, without departing from the principles involved,-.it. .is :-.n0,t intended to limit the invention to .suchmatters except to the extent set forth intherappended claims.

1 Whatis claimed-is:

1.; Aships davit having a translating and tiltingupstanding cradle: with an upper frontward extending. neck terminating in a head from which, by cablesand sheaves boat lowering and hoisting; operations are effected and downward extending legs at front and back carrying guide rollers in combination with a system of cradleguiding" tracks normally nested longitudinally and substantially fiatwise near the ship deck and having longitudinal ways engaged by such cradle rollers, the first track being a fixed straight track with its way engaged by a cradle front roller; the. second track beingv a front-hinged up swingable straight track normally parallel and adjacent to the fixed track, with its way engaged by a cradle front roller, so that said track is locked down by the cradlerollers cooperating with the fixed track against upswinging except when said rollers are intheir front positions in alignment with theatsis of upswing; the third track being a back-hinged unswingable track adjacent to the. front-hinged,traciz, withits way engaged by a cradle back roller; with a connecting sliding pivot device between said fronthinged and back-hinged tracks compelling them to swing in unison but about their" different axes as the cradle bacl; leg swings with the backhinged tract; during the tilting of the cradle, and said sliding pivot device acting also to lock down the back-hinged trackso long as the fronthinged track is locked to the fixed track; .a charged spring motor arranged continuously to urge the cradle from its normal back towardits and a controlling winch acting. through connecting cables to bring-about, in cooperation with the springmotion, launching operation steps including the translational shift of the cradle from its normal back position to followed by. its front! ward tilt to carry the cradle head and suspended boat to full outboard position followed by the lowering of the boat, and stowing operations substantially the reverse thereof.

2. In a spring-actuated davit, a cradle comprising a body portion, support a load hook, a single-foot inboard log, a double-foot outboard leg, with said feet spaced transversely. apart and giving lateral stability to the cradle, and rollers on each side of each of the said three davit feet, each of said rollers adapted to roll with the cradle from inboard stowed position to, outboard position in separate tracks; such tracks including a first track pair normally level and engaging the rollers of the said single-foot inboard leg, and being hinged at their inboard end andinterconnected to swing upland down as a unit at their outboard end; and with a second track pair normally level and engaging the inner rollers of the said double-foot outboard leg, said tracks being hinged as a unit at their outboard ends to swingas a unit up and down at their inboard end; and with a fixed third pair of level tracks engaging the-outer rollers of said doublefoot outboard leg; and the said outboardlyhinged tracks and the said inboardly-hinged tracks having means slidingly connecting one to one another to cause simultaneous upswing duringv outboard tilting of .the cradle.

davit comprisinga slidable and tiltable ahead atop said bod; to

upstanding cradle having a high frontward extension terminating in a head from which depends a floating block and load hook for boat lowering and hoisting operations and having downward extensions with low feet at the cradle front and back carrying front and back guide rollers, in combination with three cradle-guiding tracks normally grouped longitudinally near the ship deck and having longitudinal ways engaged by the cradle foot rollers, the first track being fixed and straight with its way engaged by a first cradle front roller; the second track being straight and front-hinged for upswing and arranged normally alongside the fixed track, with its way engaged by a second cradle front roller coaxial with the first so that said track is normally locked down by the front cradle rollers cooperating with the fixed track but becomes released for upswing when said front rollers are shifted to their front positions in alignment with the front axis of track upswing; the third track being a back-hinged upswingable track normally alongside the front-hinged track, with its way engaged by a cradle back roller; and a sliding pivot device interconnecting said front-hinged and back-hinged tracks compelling them to swing simultaneously as the cradle back foot swings with the back-hinged track during the tilting of the cradle, and said sliding pivot device acting also to lock down the back-hinged track and so prevent cradle tilting so long as the fronthinged track is locked down; a continuously charged spring motor having pulling connections to urge the cradle to shift frontwards; and a controller winch acting through cables extending to the cradle head and floating block to bring about launching operations of shift of the cradle from its normal back position to its frontmost position, followed by its frontward tilt to carry the cradle head and suspended boat to full outboard position, followed by the lowering of the boat; with stowing operations substantially the reverse thereof.

4. A davit comprising a cradle slidable and tiltable frontwardly and backwardly having a high frontward extension providing a head from which depends a floating block and load hook, and having downward extensions with low front and back feet carrying front and back guide rollers, in combination with three track means arranged longitudinally and having longitudinal ways, the first track means being fixed and. straight with its way engaged by a first cradle front roller; the second track mean being straight and front-hinged for upswing and arranged alongside the fixed track means, with its way engaged by a second cradle front roller; the third track means being a back-hinged upswingable track means alongside the front-hinged track means, with its way engaged by a cradle back roller; and a sliding pivot device interconnecting said front-hinged and back-hinged track means compelling them to swing simultaneously as the cradle back foot wings with the back-hinged track means during the tilting of the cradle; a continuously charged resilient spring device having cable connections to the cradle to shift it frontwards; and a control means acting through a cable extending to said cradle and the floating block, namely by paying out cable to bring about its frontward shift, followed by its frontward tilt to full outboard position, and then the lowering of the boat; with reverse stowing operations by taking in said cable.

5. A davit as in claim 4 and wherein the front 18 downward extension of the davit is forked to provide spaced apart front feet and thereby the stability of a three legged mounting.

6. A davit as in claim 4 and wherein at least the first and second track means each comprises tracks duplicated in symmetrically opposite pairs with the fixed track means at the outside and the front-hinged track means intermediate and the back-hinged track means at the inside; and wherein the cradle down-leg at the front is divided to afford left and right feet, each carrying an outer and an inner roller to engage the fixedand the front-hinged track means.

7. A davit a in claim 4 and wherein the sliding pivot device between the front-hinged and back-hinged track means consists of a longitudinal guide channel on the back-hinged track means engaged-by a projecting runner stud in the front-hinged track means; with devices to start the upswing and later downswing of said track means.

8. A ship davit comprising a cradle slidable and tiltable frontwardly and backwardly and having a highfrontward extension providing a head from'which depends a floating block for lowering and hoisting the boat, and the cradle body having downward extensions with terminal front and back feet carrying front and back guide rollers, in combination with three cooperative tracks arranged longitudinally of the davit and having longitudinal ways, one track being fixed and straight and having its way engaged by a first cradle front roller; a second track being straight and front-hinged for upswing in an upright longitudinal plane and havingits way engaged by a second cradle front roller; the third track being a back-hinged upswfingable track alongside the front-hinged track, and having its way engaged by a cradle back roller; together with a slidable device interconnecting said fronthinged and back-hinged tracks compelling them to swing upward and downward in unison as the cradle back foot swings upward and downward with the back-hinged track during tilting movements of the cradle; a continuously charged spring motor means acting through cable connections to the cradle for tending to shift the cradle frontwards; and a control means, acting through a cable extending from the control means to said cradle and to the floating block, adapted to pay out cable thereby in cooperation with the spring means to bring about the cradle frontward shift,

succeeded by its frontward tilt to full outboard position, and the lowering of the boat; with reverse operations for taking in said cable and stowing the boat.

9. A davit as in claim 8 and wherein is a stop means acting as a barrier to limit the front slidmg of the cradle front rollers in the ways of at lease one of the tracks other than the backhinged track, said stop means being located to stop the frontward shift of the cradle in a position with its front rollers in axial alignment with the hinge fulcrum of said front-hinged track, whereby said track is not locked down, but is free to swing up when the stop means is in eifect.

10. A davit as in claim 8 and wherein is a stop means operable to limit the degree of front tilting of the cradle by stopping the sliding of said slidable device during the upswinging of the front-hinged and back-hinged tracks with the frontward tilting of the cradle.

11. A davit as in claim 8 and wherein is a resilrent spring motor device continuously charged and connected between the davit base and one.

of said two interconnected hinged tracksain': such:

positionasi to apply its resilient? force: to: start and cause upswingingof both. of said; hinged. tracks, for assisting the frontward tilting action of'the cradle.-

12. Aidavit as in claim Band whereinthe continuously-charged cradle-shifting spring-motor: means comprises an elongated coil spring". errcased.- in telescoping tubes of: whichithe movable tube is connected by a cable extending ancli clamped to the cradle whereby to provide spring pull through the cable-upon thecradlethereby to efiect the frontward' shift of the latter.-

13. A davit as inclaim 8'wherein. thecradle head carries cable sheavescooperating with the floating: block, and whereinthecable control means is-a winch whose cable whichcauses the operative cradle movements; by paying out cable for launchingand taking in cable for: stowingthe boat, is disposed as follows: from the controlling Winch the cable extends, with the aid: of idler" pulleys, frontward tolthe cradle and-thence to a first sheave on the cradle head, and thence downward and around'the floating blocksheave in the suspended block from which the-boat ishung; and thence upward and around a second head sheave, and thence from the cradlerearward to a terminal anchoring point beyond the cradle.

14; Atdavita as i'n clairrr l3-and whereini isia'n: upstanding fixed post rearward. of the. retracted:

deadcenter at. the sliolable. device which consnects: the rear-hinged to" the front-hinged: tracks; saidmeans consisting in mutual contact pieces, one on the front-hingeditrackiandithe; second on the cradle inposition: tothrust dorwnl on. the first contact piece by reason of: the backswing of the cradle, thereby to. start the down swing of the front-hingedtrackiandpromote the: downswing of both hinged tracks and thee-comepletion'cfthe back tilting of the cradle;

WILLIAM E. ELLING} References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,260I7'72 Coates et a1; Oct. 28, 1941 2,319,854v Elling -May 25; 1943. 

